颈动脉注射辣椒素激活脑干心血管相关核团的儿茶酚胺神经元

在外周压力感受器去神经支配的大鼠上，用Ｆos蛋白和酪氨酸羟化酶（ＴＨ）的双重免疫组化方法，研究辣椒素的效应是否通过激活脑干核团内儿茶酚胺能神经元而诱发。结果显示，颈动脉注射辣椒素诱发脑干中最后区（ＡＰ）、孤束核（ＮＴＳ）、巨细胞旁外侧核（ＰＧＬ）和蓝斑（ＬＣ）等多个部位出现大量ＦOS样免疫反应（ＦＬＩ）神经元和双标神经元，辣椒素受体阻断剂钌红（ＲＲ）或ＮＭＤＡ受体阻断剂ＭＫ－８０１可明显减弱此效应。以上结果表明，辣椒素的兴奋效应通过激活儿茶酚胺能神经元而诱发，辣椒素受体和／（或）谷氨酸介导这一效应。

Activation of catecholaminergic neurons in the brainstem nuclei involved in cardiovascular regulation following intracarotid injection of capsaicin in rats

The present study was undertaken to define whether the effects of capsaicin were induced by activating the catecholaminergic neurons by double immunohistochemical method for Fos and tyrosine hydroxylase (TH). The results demonstrated a robust Fos like immunoreactive (FLI) and double labeled neurons in area postrema (AP), the nucleus tractus solitarius (NTS), nucleus paragigantocellularis lateralis (PGL) and locus coreruleus (LC) following intracarotid injection of capsaicin. These responses to capsaicin were significantly attenuated by pretreatment with either a capsaicin receptor antagonist ruthenium red or a NMDA receptor antagonist MK 801. The present study suggested that capsaicin might activate the neurons of the brainstem nuclei involved in cardiovascular regulation, The results supported the hypothesis that the excitatory effects of capsaicin were induced by activating the catecholaminergic neurons of brainstem nuclei involved in cardiovascular regulation. Capsaicin receptor might mediate the effects of capsaicin with the involvement of glutamate.